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HP Formula:
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This calculation estimates a vehicle's horsepower based on its weight and quarter-mile elapsed time (ET). It provides a mathematical approximation of engine power output using performance data.
The calculator uses the formula:
Where:
Explanation: The formula relates vehicle weight and quarter-mile time to estimate horsepower, with the cubic relationship reflecting the physics of acceleration.
Details: This calculation is valuable for performance enthusiasts, automotive engineers, and racers to estimate engine power without dynamometer testing, helping with vehicle tuning and performance comparisons.
Tips: Enter vehicle weight in pounds and quarter-mile elapsed time in seconds. Both values must be positive numbers for accurate calculation.
Q1: How accurate is this HP calculation?
A: It provides a reasonable estimate but may vary based on traction, aerodynamics, transmission efficiency, and other factors. Dyno testing is more accurate.
Q2: Does this work for all types of vehicles?
A: It works best for rear-wheel drive vehicles with good traction. Front-wheel drive and all-wheel drive vehicles may have different results due to power loss differences.
Q3: What is a typical quarter-mile time for performance cars?
A: Performance cars typically range from 11-14 seconds, while supercars can achieve times under 10 seconds. Stock family cars usually run 15-17 seconds.
Q4: Should I use curb weight or race weight?
A: For most accurate results, use the actual race weight including driver, fuel, and any additional equipment during the quarter-mile run.
Q5: Why is the constant 5.825 used in the formula?
A: This empirical constant was derived from analysis of drag racing data and provides the best fit for the relationship between weight, time, and horsepower.